How to design lightning protection system

how to design lightning protection system

Solutions for Lightning Protection, Bonding, and Grounding

Sep 19,  · The Lightning Protection Institute (LPI) adopts the latest edition of the NFPA Standard as its reference document for system design. LPI advocates use of UL as the third-party inspection authority for components according to their documents UL Bonded Lightning Protection offers lightning and surge protection system design, supplies and installation in Florida with offices in Tampa and Jupiter.

Lightning strikes the ground throughout the world times every second. It is known as one of nature's most destructive elements A single bolt can carry up to one billion volts of energy and can reach temperatures of 28,'c. As a result of changing weather patterns, lightning strikes in the UK are increasing year on year. A lightning protection system is designed to give the energy from a lightning flash a safe path to earth.

Your safety and the efficiency of your business depends on the safety measures you undertake. Whether it is a domestic, commercial or historic building we can help to protect your building.

Contact us to find out if we can assist you with any aspect of lightning protection. From completing a risk assessment, design, installation or maintenance of a lightning protection system. Providing you with peace of mind, a safer environment and better protection during the next thunder storm. Lightning Protection Services For all of your lightning protection and access requirements, we are here to help.

Why Lightning Protection? Why Lightning Protection Services? Do not what is your objective when applying for a job a lightning strike affect you.

Visit Our Contact Page for details. Lightning Protection Find Out More. Earthing Systems Find Out More. Height Services Find Out More.

LPI’s 4-Step Approach to Lightning Protection

Lightning protection system design. Considerable material is used to make up lightning protection systems, so it is prudent to consider carefully where an air terminal will provide the greatest protection. Historical understanding of lightning, from statements made by Ben Franklin. (ESD) Protection Design Guide Table of Contents Page Introduction 2 General Purpose ESD Protection Ethernet and Lightning Surge Protection 5 Low Capacitance ESD Protection Application Specific Device Selection • USB • USB • USB (Two Device Solution) • USB (Integrated Solution) • USB (Type C Compliance) • HDMl. LPI are a fully Australian-owned manufacturer and supplier of direct strike, power line, signal & data and earthing lightning protection solutions. Lightning Protection International has been honoured with the Technology and Innovation Award at the Tasmanian Export Awards.

The Lightning Protection Institute is a nationwide not-for-profit organization founded in to promote lightning protection education, awareness, and safety. The lightning protection industry began in the United States when Benjamin Franklin postulated that lightning was electricity, and a metal rod could be used to carry the lightning away from a building.

Lightning is the direct cause of over 50 deaths and injuries each year, and it is difficult to protect individuals in exposed outdoor areas. Most of these property losses could be minimized, if not eliminated, through the implementation of proper lightning protection for structures.

The National Fire Protection Assoc. NFPA publishes document titled Standard for the Installation of Lightning Protection Systems considered the national design guide for complete lightning protection systems in the United States.

NFPA published its first document on lightning protection in The lightning protection Standard is reviewed on a three-year cycle for updating. NFPA includes lightning protection for typical building construction in Chapter Four as requirements for ordinary structures. The document covers many specialty constructions from hazardous materials storage to boats and ships to open picnic structures, and gives recommendations for personal safety outdoors.

NFPA provides the best we know today in theory and technology on protection systems tested by experienced industry professionals in a legally recognized format. Product testing for lightning protection material components in the factory prior to shipment for listing and labeling is handled by Underwriters Laboratories, Inc.

The UL Standard 96 addresses the minimum requirements for construction of air terminals, cable conductors, fittings, connectors, and fasteners used in quality lightning protection systems. UL has inspection personnel who visit production facilities on a regular basis to verify compliance for continued use of their approved merchandise labels.

Field inspection of completed lightning protection installations may also be arranged with UL through installing contractors listed in their program. LPI publishes this document , based on NFPA , with additional explanatory material helpful to installer and inspector member personnel.

Individuals sit for exams which include the requirements of the above listed lightning protection Standards and application of those principles to design examples.

Membership renewal is required each year with additional examinations taken approximately every three years when the national Standards are updated. Contracting with professionals qualified through the LPI process ensures an added level of quality assurance for initial system installation and a resource for future inspection and maintenance of existing systems.

LPI-IP provides a certification service more thorough and complete than any previous inspection program from LPI or others currently available in the marketplace. Through the use of check points, reviews, and on-site inspections, LPI-IP system certification ensures safety using qualified installer personnel and independent inspectors.

This is a critical element to the specifier, owner, and property insurer providing verification by a third-party independent source of quality lightning protection installations. Lightning protection systems for structures are typically not a requirement of national building codes, although the Standards may be adopted by the authority having jurisdiction for general construction or specific occupancies.

Since lightning protection may be considered an option, it is crucial that the specifier, construction contractor, and property insurer be familiar with the national Standards to provide the highest level of safety available.

Lightning protection systems have a remarkable record of protecting against physical danger to people, structural damage to buildings, and failure of internal systems and equipment.

The value received begins with proper design, continues through quality installation practices, and must include inspection and certification.

These Standards are based on the fundamental principle of providing a reasonably direct, low-resistance, low impedance metallic path for lightning current to follow, and making provisions to prevent destruction, fire, damage, death, or injury as the current flows from the roof levels to below grade.

The Standards represent a consensus of authorities regarding basic requirements for construction and performance of qualified designs and products. Based on sound engineering principles, research, records of tests and field experience, a complete protection system is expected to create personal and structural safety from lightning and its secondary effects. The Standards are under continuous review for new products, construction techniques, and validated scientific developments to address the lightning hazard.

There are five elements that need to be in place to provide an effective lightning protection system. Strike termination devices must be suitable to accept direct lightning attachment and patterned to accept strikes before they reach insulated building materials.

Cable conductors route lightning current over and through the construction, without damage, between strike terminations at the top and the grounding electrode system at the bottom. The below grade grounding electrode system must efficiently move the lightning to its final destination away from the structure and its contents. Bonding or the interconnection of the lightning protection system to other internal grounded metallic systems must be accommodated to eliminate the opportunity for lightning to sideflash internally.

Finally surge protection devices must be installed at every service entrance to stop the intrusion of lightning from utility lines, and further equalize potential between grounded systems during lightning events.

When these elements are identified properly in the design stage, incorporated into a neat workmanlike installation, and no changes to the building occur, the system will protect against lightning damage.

Elements of this passive grounding system always serve a similar function, but the total design is specific for each particular structure. Lightning protection components are made from materials that are resistant to corrosion and they must be protected from accelerated deterioration. Many system components will be exposed to the atmosphere and climate. Combinations of materials that form electrolytic couples in the presence of moisture shall not be used.

Current carrying system components must be highly conductive. Prevailing site soil conditions will impact in-ground system components. System materials must be coordinated with the structural materials in use — including flashings, copings, ventilator housings, various roofing systems — to maintain the moisture envelope for the intended life of the building.

Copper, copper alloys including brass and bronze , and aluminum are the basic system component materials. They serve the best combination of function for current carrying and weathering. Since aluminum materials have slightly lower current carrying capability and mechanical strength than similar sized copper products, listed and labeled materials for lightning protection include larger physical size parts. Water running off copper will oxidize aluminum and galvanized surfaces, so coordination of system design must include galvanic considerations for potential mounting problems.

Qualified bimetallic fittings are used to coordinate system components for required transitions from aluminum to copper. These may include listed products for the purpose, or in some cases stainless steel components. Aluminum can never come in contact with the earth or soil. Aluminum should never contact alkaline based paint surfaces or be embedded directly in concrete. If any product is subject to unusual mechanical damage or displacement, it may be protected with a molding or covering, but care must be exercised to allow strike terminations and other roof mounted components to serve their function in accepting attachments.

Lightning protection components below the strike terminals may be concealed within the building below the roof level during construction or when accessible.

The speed of lightning current and splitting the flow among multiple paths will not permit components to heat to any instantaneous ignition temperature hazardous to typical building materials. Incorporating the system into the construction allows interconnection of structural metal framing and internal grounded systems, and provides protection against displacement and maintenance issues which are beneficial in extending the life of a system.

Materials suitable for use in lightning protection systems are listed, labeled, and tested according to UL Standard Consideration for conductor design includes maximizing surface area to carry lightning and flexibility of the configuration to make bends and turns required in installation practices. Air terminal bases efficiently accomplish the transfer of a strike from termination device to cable conductor and securely mount to various building surfaces under severe weather conditions.

Splicing fittings must maintain contact with conductor lengths adequate to accomplish current transfer and weather the exposed environment. Grounding electrodes must provide the proper earth contact to disperse the charge and satisfy requirements for life cycle suitability in various soil compositions.

Bonding devices are sized to provide adequate interconnection of systems to create potential equalization throughout the structure. Surge Protection Devices are qualified at higher current levels to meet the needs associated with lightning attachments.

Strike termination devices serve the system function of accepting the direct lightning attachments. They represent the umbrella against penetration of lightning to non-conductive building materials to guard against fire or explosion. Therefore, in some cases construction elements may be incorporated as strike terminations. Tall masts or overhead ground wires similar to power transmission line protection may serve as strike terminations.

In most cases, however, small specific purpose air terminals constitute the majority of strike termination systems. These unobtrusive components are preferred for ease of mounting and aesthetic reasons, and can be coordinated into a most effective configuration for all typical building constructions.

The atmosphere surrounding us is electrically charged, but free air maintains a relatively balanced ion distribution. When we raise a building into the air, a tree or even a person to a lesser extent, we change that electrical balance. The electrical field accumulates to change points in the geometry of ground mounted objects. Items like ridges and particularly ridge ends, edges of flat roofed buildings and even more the corners become points of accumulation for ions that increase susceptibility to lightning attachments.

The taller the structure and the more severe the planar changes like a vertical wall to a horizontal flat roof the greater the opportunity for attachment at these critical junctions. Some lower potential lightning strokes could theoretically attach on flat planes away from strike terminations designed to the Standards, but the consequences are within acceptable limits for ordinary construction.

Considering the lower energy level required for a bypass, the other structural grounding components included in a complete lightning protection system, and the random probability for connection with a system component anyway, this method of building protection is considered most efficient. A zone of protection exists from any vertical strike termination device and more than that from a vertical fully protected building level.

Zone of protection is described in the lightning Standards using a feet 46 meters radius sphere model to identify items under the protection of higher system elements or building extensions to distances that require further protection by additional strike terminals.

This is like rolling a feet 92 meters diameter ball from grade up against and then over a building to the opposite grade level in every conceivable direction. If the ball touches insulated building material, then an additional strike terminal is added. Areas supported by strike terminals, a strike terminal and grade, and vertical walls are then under the protection of properly designed system elements.

The strike termination system defends the structure against lightning attachment by providing preferred attachment points. Copper or aluminum air terminals are preferred in most cases based on their conductivity and suitability to exposure to weather. Qualified prominent metallic building elements may also serve the function. In special circumstances where lightning cannot be allowed to penetrate, the use of tall masts and overhead ground wires used in a reduced zone model can provide additional protection.

Protecting things like lighting standards or trees can provide some area protection based on the zone model. Strike termination design configuration is the first key element to providing a complete lightning protection system. The conductor system component of complete lightning protection includes main sized cables, the structural steel of a building, and bonding or interconnection wires to internal grounded building systems.

The main conductors perform the current carrying function from the strike termination devices to the grounding system. Main cables are highly conductive copper or aluminum that perform well in an external environment.

Lightning seeks a path toward ground, so even with very conductive materials, the routing of cables needs to be maintained in a horizontal or downward coursing. This is similar in concept to the gravity flow of water on sloped flat areas to roof drains or in gutter to downspout systems. Cables need to be routed using long smooth bends of no less than 90 degrees. Lightning will place significant mechanical force on cables, and sharp bends or corners can be damaged or lightning can arc over in the worst cases.

This mechanical force can be compared to sending pressurized water through a fire hose — the conductor will try to straighten itself creating a damage concern for splice fittings, fasteners, or the conductor itself. Copper and aluminum main cable conductors for lightning protection are designed to a smooth weave or rope-lay standard using smaller gauge individual wires.

This construction allows a maximum surface area per unit weight of conductor to accommodate lightning which travels quickly on the surface. This construction also allows for easier bending and forming of the conductor system along, around and over building construction elements.

Exposed conductors are fastened at maximum three feet intervals to maintain the system in place against wind and weather.

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